Sulfur dioxide in a fluid often has an adverse effect if the fluid is used in some industrial applications. For example, sulfur dioxide in a fluid may induce metal corrosion when the fluid is used in applications requiting the contacting of the fluid with a metal or metal surface. These fluids can be a gas, an aqueous liquid, a non-aqueous liquid, or combinations of any two or more thereof, such as, for example, a sulfolene compound or a sulfolane compound.
Sulfolane compounds are useful in a variety of industrial applications such as, for example, in pesticidal compositions, intermediates in the production of other organic chemicals, selective solvents to separate aromatic compounds from petroleum fractions, and selective solvents in alkylation of olefins.
Sulfolane compounds are generally prepared by catalytic hydrogenation of the corresponding sulfolene compounds. The sulfolene compounds are prepared by the reaction of a conjugated diene such as, for example, 1,3-butadiene, and sulfur dioxide at elevated temperatures.
However, the sulfolene compounds thus-produced are generally unstable and tend to decompose at mildly elevated temperatures into an unsaturated organic compound and sulfur dioxide. Furthermore, when the sulfolene compounds are used to prepare the corresponding sulfolane compounds by catalytic hydrogenation, the initiation of hydrogenation reaction may also increase the temperature enough to result in some decomposition of the sulfolene. Some of these decomposed products polymerize and the resulting polymer coats the hydrogenation catalyst significantly reducing its activity. Moreover, unreacted sulfur dioxide and the sulfur dioxide obtained from decomposition of sulfolene compounds also interfere with the subsequent catalytic hydrogenation. If excess sulfur dioxide is present in the resulting sulfolane compounds, the sulfolane compounds become corrosive towards metals and results in some undesirable side effects when the sulfolane compounds are used in industrial applications. These sulfur dioxides must be removed or substantially reduced.
Processes have been developed for inhibiting the formation of polymers and reduction of sulfur dioxide in the production of sulfolane compounds. For example, amines have been used as inhibitors in reducing the amount of polysulfone polymer formation. Oxidizing agents have been used to reduce sulfur dioxide and other impurities. However, there is an ever-increasing need to develop still more effective methods of removing sulfur dioxide content in sulfolene and sulfolane compounds thereby greatly improving the production of superior sulfolane compounds.